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J L Bada

Publications and source records attributed to J L Bada.

102 records · Page 6Linked to original sources
PubMed1968

Ammonium ion concentration in the primitive ocean.

If ion exchange on clay minerals regulated the cationts in the primitive ocean as it does in the present ocean, the pH would have been 8 and the K(+) concentration 0.01M. Since NH(4)(+) and K(+) are similar in their claymineral equilibria, the maximum NH(4) (+) concentration in the primitive ocean would also have been 0.01M. An estimate of the minimum NH(4)(+) concentratin is 1 x 10(-3)M, based on the reversible deamination of aspartic acid and the assumption that aspartic acid is necessary for the origin of life. The rate of this nonenzymic deamnination is rapid on the geological time scale.

Ammonia↗
PubMedDate not supplied

[Differential characteristics of AIDS in foreign immigrants].

BACKGROUND: AIDS in foreign migrants can have specific characteristics compared with that of Spanish patients. METHODS: Cross-sectional study, including cases from the Barcelona AIDS register diagnosed from 1988 to 1998. Global characteristics of migrants are compared with those of Spanish patients. Adjusted odds ratio (OR) with 95% confidence interval (CI) were calculated through logistic regression. A formal analysis was also performed. RESULTS: Among the 4,663 patients included, 5% were migrants. 33% of patients were diagnosed with AIDS 10 years after having migrated to Spain. They differentiate at the multivariate level by sex (OR [male]: 1.70; CI: 1.10-2.64), district of residence (OR [district I]: 2.07, IC: 1.50-2.87) and transmission pattern (OR [other than injecting drug users]: 4.08; IC: 2.77-5.99). No significant differences in survival were showed. CONCLUSIONS: The percentage of migrants among AIDS cases in Barcelona is low. Migrants are more frequently men, more often live in the inner city and are less frequently injecting drug users.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Accelerator mass spectrometry radiocarbon ages of amino acid extracts from Californian palaeoindian skeletons.

A decade ago, aspartic acid racemization ages were determined for some skeletal remains found in California, near La Jolla, Del Mar and Sunnyvale, suggesting that people were present in North America during the Upper Pleistocene. These ages were obtained from the aspartic acid racemization rate, which was calibrated using a radiocarbon date of 17,150 +/- 1,470 yr BP determined for a skeleton found in Laguna Beach, California. These studies generated an intense controversy not only about the antiquity of human beings in the New World but also about the validity of racemization-based ages, and prompted efforts to date the finds by other means. Here we have used accelerator mass spectrometry (AMS) to determine the radiocarbon ages of the amino acid extracts used in the original racemization studies. Our studies indicate that some of the controversial Californian skeletons, which had been assigned to the Upper Pleistocene, are in fact Holocene.

Amino Acids↗